Refrigerating apparatus



Penman. 29, 1933 PATENT OFFICE H liJiJ RIl'z:HEATING APPARATUS LawrenceA. Philippi Detroit, Mich.,"assignor to Nash-Kelvinator Corpo'ratiomDetroit, Micln, acorporation of I Application July 2, 1937, Serial No.151,571

1 Claim. (cite-125) This invention relates to refrigeration and moreparticularly to an improved method of and apparatus for refrigeration, Y

One of the objects of my invention is to provide an improved arrangementfor conducting liquid refrigerant to a refrigerant evaporating zonelocated above the condensing zone and to provide an improved arrangementfor controlling the flow of liquid refrigerant .to the evaporating zone.

Another object of my invention is to provide an improved method ofrefrigeration which consists in elevating liquid refrigerant to anevaporating zone which is located at a point above the condensing zoneby utilizing the application of heat for conducting the liquidrefrigerant and control-.- ling the flow of liquid refrigerant to thepoint of heat application in accordance with changes in pressuresexisting in the evaporating zone.

: Another object'of myinvention is to maintain a substantially constanttemperature differential between primary and secondary refrigeratingsystems by controlling the pumping of liquid refrigerant to theevaporating zone of the secondary system in accordance with the changesin the environment 'air temperatures adjacent the refrigerant pumpingdevice and by controlling the flow of liquid refrigerant to therefrigerant pumping device in accordance with changes in m pressureswithin the secondary refrigerating sys-' tem.

Other objects and advantages of the present invention will becomeapparent upon perusal of the following description, reference being hadto 35 the accompanying drawings in which are illustrated preferred formsof my invention. 7

In the drawings:' Fig. lis a diagrammatic view of a refrigerating systemincluding primary and secondary rem frigerating systems embodyingfeatures of my invention; r

Fig. 2 is a diagrammatic view of a modified form of secondary system;

Fig. 3 is a view in cross-section of a pressure 15 responsive valveembodying features of my invention; i

Fig. 4 is a diagrammatic view of another modified form of secondaryrefrigerating systems; and Fig. 5 is a diagrammatic view of a stillfurther modified form ofsecondary system. V I

In some instances in the use of primary and secondary refrigeratingsystems itlias been found desirable to position the refrigerantevaporator of the secondary refrigerating system entirely 55 above thecondensing element of the secondary -system. One example of this use isfound in the refrigeration of motor' vehicles, such as trucks, whereinthe refrigerant evaporating element is positioned adjacent the uppermostpart of the compartment wherein foods are stored for deliv- 5 cry andthe condenser is located in the lower portion of the vehicle body andcooled by ice or blocks of CQz. By this arrangement the ice or blocks ofCOzconstitute the primary refrigerat ing system and may be readilyplaced in contact with the condenser of the secondary system without,elevating such primary system to undue height to which the secondaryrefrigerant evaporator is located. in some installations it is founddesirable to' associate with the secondary condenser a refrigeratingsystem which is automatic and is of the so-called compression type. Ineither case wherein-the secondary condenser is located below thesecondary evaporator some provisions m ust be made for pumping orotherwise conducting liquid refrigerant from the secondary condenser tothe secondary evaporator. In many instances it has been found desirableto maintain the temperature of the secondary system evaporatorconsiderably above the lowest temperatures prevailing in the primarysystem.

In accordance with my invention I provide an improved arrangement forconducting liquid re-- frigerant to a refrigerant evaporating element ofa secondary-refrigerating system, which element is located above thecondensing element of the system, andalso provide an improvedarrangement for positively controlling the temperatures existing in thesecondary system.

Referring to the drawings and particularly Fig. 1, the numeral 20designates in general a com-- partment which is provided for the storageof foods and the like and may be the compartment of any suitablerefrigerating apparatus such as meat.boxes,'household refrigerators, orcooling compartments of motor vehicles and the like. The compartment 20is maintained at a substan-' tially constant temperature by means of asecondary refrigerating system 22 which includes a heat absorber -orrefrigerant evaporating ele- 5 ment 24 disposed within the enclosure 20and a heat dissipator or condenser 26 for dissipating; the heat absorbedin the element 24.- Liquid refrig'erant delivered from the condenser 25to p the evaporator 24 by a liquid supply conduit 28.

The conduit 28 has an outlet 30 associated with a vessel 3| which isconnected-in open communlcation with inlet 32 and outlet 33 oftheevaporator 24. Gaseous refrigerant is conducted from the evaporator24 to the condenser 26 through a por lift pump or trap 48 which isconnected in the liquid supply line between the condenser 26 and theevaporator 24. This vapor lift pump or trap is formed in the generalshape of a U havconduit 28. By this arrangement liquid .refriging bothends 4| and 42 connected to the supply erant leaving the condenser 26will first pass into the leg 42 of trap 48 and by the application ofheatto the trap 48 vaporization will take place to such an extent thatit will lift liquid refrigerant upwardly through .the conduit 28 intothe vessel 3| whence it passes into the inlet 32 of the evaporator 24.Thetrap 48 may beplaced in any suitable position desired where it willbe subject to changes in the. temperatures of the environment air or, ifdesired, any generated heat.

' However, it has been found that in systems of this type the condenserand evaporator may be completely insulated within certain compartmentsof a refrigerator and the trap 48 exposed to the environment airsurrounding the refrigerator where it will receive sufiicient heat tocause liquid refrigerant to be elevated to the evaporaor 24. I

In order to control the flow of liquid refrigerant to the evaporator 24I have provided an automatic pressure responsive valve 58. which, asshown in Fig. 1, is connected between the condenser 28 and the trap 48.This valve is set so as to be responsive to changes of pressures with-'in the system so as to allow the fiow of liquid refrigerant from thecondenser 26 to the trap 48 when the pressure within the evaporator 24'reaches a predetermined high value. When this occurs the temperature ofthe evaporator 24 is such that there is a need for. refrigeration bythat evaporator and accordingly the valve permits the flow of liquidrefrigerant to the trap '48 to thus cause the fiow of liquid refrigerantto the evaporator 24 in response to that refrigeration requirement Anysuitable means may be provided for cooling the condenser 26 and asherein disclosed, I have provided an automatic refrigerating system ofthe compression type-for automatically maintaining substantiallyconstant temperatures within the condenser 28-so as to provide for main-Preferably the primary system 52 is intermit- 'tently operated under thecontrol of a thermo- I taining a substantially constant temperaturedifferential between the primary refrigerating syswherein it isliquefied and from which it is deliveredto the float valve mechanism 68.The

fioat valve mechanism 68 controls thefiow of liquid refrigerant toevaporator 51 through conduit 84. The compressor 54 is operativelyconnected with motor 55 for actuating motor 54'.

stat 88 which includes thermo-bulb 68 connected to evaporator 51, so asto be responsive to changes in temperature within that evaporator foropening and closing the motor circuit upon predeterv mined increase ordecrease in temperatures within the evaporator 51 as is well understood.Other primary systems may be used if desired such, for example, as ablock of CO2 or'the like.

While the primary system 52 may be operated at any desired temperatureeither above or below freezing, the secondary system may be adjustedreadily for operating atany desired temperature above the temperature ofthe evaporator 51 of the primary system. This is accomplished by use ofthe adjustable valve 58.

In accordance with my invention I provide the valve 58 for controllingthe flow of liquid refrig-.

erant in the secondary system and in so doing provide for maintaining apredetermined temperature differential between the primary and secondaryrefrigerating systems. The refrigerants used in the primary andsecondary systems may be the same ordiflerent refrigerants as desiredand may be any of the refrigerants now well known in the art.

Referring now to Fig. 3, the valve 58 comprises in general a casing 18having ports 12 and 14 to which conduits 28 and 31 are connectedrespectively. Within the casing 18 is disposed valve proper 16 whichcooperates with valve seat 18 for controlling the flow of refrigerantbetween conduits 31 and 28. The valve proper l6 is'carried by an annulardisc 88 to which is sealed bellows 82. The opposite end of bellows 82 issealed to an annular disc 84 whichrests upon a shoulder 85 formed in thecasing 18. Upon an increase of pressure within the casing 18 the bellows82 tends to collapse and in so doing moves the valve 16 away from itsseat I8. At this time communicationis established between conduits 31and 28. The bellows tends to collapse in opposition to compressionspring 98 which continuously tends to urge the valve 18 towards seat 18.Theeffectiveness of the spring 98 may be controlled by adjustment screw92. Preferably the annular disc 84 is sealed to the shoulder 85 so as toprevent leakage of refrigerant out of the casing and about the screw 92.By this arrangement it will be noted that when the pressure, within theevaporator 24 reaches a predeterw mined value the pressure within theliquid supply conduit 28 will beequivalent to the pressure withinevaporator 24 and this pressure will be the same within the casing 18toexert itself upon'the bellows 82 to collapse said bellows. When thistakes place the valve 16 is in open position andallows liquidrefrigerantto fiow from the condenser 26 into trap 48 where the refrigerantis-subjected to heat so; as to provide a vapor lift pump forconductingsaid liquid refrigerant into the evaporator 24. Any setting of the valve58 for different temperatures in the secondary system may be had asdesired.

When my invention is employed, for "example, in household refrigerators,the primary refrigerant evaporator 51 may be completely insulated fromenvironmentair surrounding the refrigerator and may be of the sameconstruction as is now generally employed in household refrigerators forthe freezing of ice cubes and the like. .These structures are well knownand illustration and further description thereof is deemed unnecessary.Thus a refrigerator may be provided for the freezing of ice cubes byutilizing the primary evaporator for that purpose. At the same time theevaporator 24 may be disposed within a 75 p 2,138,012 food storagecompartment which may be the' compartment 20 and utilized for properpreservation of food stuffs and the like. The evaporator 24 may bedesigned of suflicient size so as to properly cool the food stuffswithout the collection of frost on its external surface, thetemperature'of that evaporator being controlled by the valve 50, which,.as previously stated, prevents the flow of liquid refrigerant to theevaporator 24 until the evaporator '24 reaches a predetermined hightemperature. If, however, it is desired to design the evaporator 24 ofasmaller size and maintain proper preservation of food stufis in thecompartment 20, the same may be operated in such a manner that frostcollects on its outer surface i when the primary refrigerating system isinoperation and the frost is allowed to melt off during periods when theprimary refrigerating system is inoperative. If, however, it is dethatits temperature constantly below freezing, the valve 50 may be set toaccomplish this, result. In this instance, however, the evaporator neednot be as large-as evaporators which either do not allow the same tomelt off during other periods of operation.

It will readily be apparent that the refrigerating system disclosed inFig. 1 may be suitablefor use for other p UOses than householdrefrigerators, and as disclosed, it will be readily appar-. ent thatadjustment may be readilyaccomplished for obtaining any temperaturesdesired.

When the system disclosed in Fig. 1 is used for 35 householdrefrigerators, it may be in' some instances desirable'to place the trap40 in heat exchange relation to the motor compressor unit of.

the primarysystein 52 so that when there is a demand for refrigerationby the thermostat 06 4c the heat given off by the motor compressor unit24, and this may be accomplished by merely ,placing the thermo-bulb 68in heat exchange-relation with the evaporator 24. Asthis modification isreadily understood by the foregoing description, 55 it is believedthat'further description and dis closure in the drawing is unnecessaryfor a proper understanding of such modification.

From the foregoing it will readilybe apparent that I have provided anewand improved refrig- 60 eratin'g system of the type including primaryand secondary refrigerating systems wherein desired temperatures may bemaintained in the secondary system in a new and improved manner and theevaporator of the secondary system may be lo- 65 cated above thecondenser of that system without in any' manner impairing theeflicie'ncy or opera- .tion of the secondary system'and that'the liquidrefrigerant in-the secondarysystem is elevated byv utilizing environmenttemperature inside or about 7 the refrigerating apparatus. "It will alsobe ap-- parent, however, that artificially generatedheat may beused forapplying heat-to trap 40 and that under either conditions of operationthe valve 50 I serves to maintain a predetermined temperature 75diiferential between the primary and secondary sired to continuouslyoperate evaporator 24 so collect frost or collect frost part of the timeand 3 systems. As shown in Fig. 1, the condenser 26 and evaporator 51are positioned in a compartment which may be of, such size andconstruction asto. provide a storage space for food articles for storingsame at low temperatures either above.

or below freezing as desired and which temperatures may be controlled bythe setting of thermostat 66. Evaporator 51 maybe attached to condenser20.

' InFig. 2 there is shown a modified-form of refrigerating systemembodying features of my invention. In this figure in the drawings thenumeral I00 designates a heat absorber or refrigerant evaporatingelement corresponding to the refrigerant evaporator 24 in Fig. 1. Theevaporating element I0'0 is disposedwlthin a compartment I02 whichcorresponds to the inclosure 20 of Fig. 1. Associated with theevaporatingelement I00 is a condenser 1 04 which corresponds tocondenser 26. A supply conduit I06 like conduit 28 .conducts liquidrefrigerant from the condenser and terminates at I08 in a vessel- IIOwhich corresponds to vessel 3i of Fig. 1.

Vessel IIO, however, is in open communication Y with the inlet end II2only of the refrigerant evaporator I00. A return conduit 4' corre-'sponding to the conduit 31 of Fig. 1 connects the I outlet end IIB ofthe evaporator directly to'the condenser I04. A pressure responsivevalve II8 and a single-tube I20, corresponding to valve 50 andtraprespectively of Fig. 1, are disposed in the supply conduit I06 forregulating the flow of refrigerant to the evaporator I00. ,A conduit I22conducts vapor from vessel IIO to a condenser I24 which may be cooled bythe same meansutilized to cool condenser I04. Preferably, a heatabsorbing element similar to evaporator 51 of the'primary system 52 ofFig. l is used to maintain condensers I04 and I24 .at asubstantiallyconstant temperature. The refrigerant condensed in condenser I22 isconducted by a conduit I26 to the supply conduit I06 where it mergeswith refrigerant from the condenser I04. The operation of system shownin Fig. 2 is similar to the operation of system shown in Fig. 1, howeverconduit I22 conducts vapor directly from vessel I I'll to auxiliarycondenser'I24. The main portion of the evaporated refrigerant in thesystemis produced "in evaporator I00 and is conducted tocondenser I04through conduit "4. The two condensers I04:

and I24 are housed in compartment I21 which corresponds to compartment95. The primary system may be associated with these two c'ondensers in amanner described in connection with Fig. 1.

' denser 20 of Fig. '1 which may likewise be maintained at-a. constanttemperature by means of a primary system such as that shown in Fig. 1.

A supply conduit B -corresponding to conduit 28 opens into a vessel I38similar to vessel 3I at I40. This vessel I38 is in open communicationAnother modified form of a refrigerating syswith the entrance I42 to theevaporator I32. It

also communicates with the end of the evaporator' throughconduits' I44and I46. Return conduit I48 which corresponds to'- conduit 31' conducts.

. refrigerant vapon fromjthe evaporator and vessel

